Extracellular GSH decreases <i>B. cenocepacia</i> invasion. Panel A.

<p>Invasion of 9HTEo- and CFTE29o- by <i>B. cenocepacia</i> LMG 16656 was assayed in presence of 0, 0.1, 1 and 10 mM GSH. The % of invasion indicates the ratio between the number of intracellular bacteria recovered from infected cells with respect to the bacteria added to the cell monolayer. Results represent means ± SD obtained by measuring <i>B. cenocepacia</i> LMG 16656 invasion in three independent experiments. Asterisks denote statistically significant results (* p<0.05; ** p<0.01 and *** p<0.0001, respectively). White bar: untreated cells; grey bar: cells treated with 0.1 mM GSH; dotted bar: cells treated with 1 mM GSH; black bar: cells treated with 10 mM GSH. <b>Panel B.</b> 9HTEo- and CFTE29o- were pretreated with 0, 0.1, 1 and 10 mM GSH for 3 hours at 37°C, washed to remove GSH and then used in the infection assay. Results, which are expressed as the mean ± SD of intracellular bacteria isolated from cells pretreated with GSH with respect to untreated cells, are the average of three independent experiments (**p<0.01; ***p<0.0001). Bar colors are as in panel A. <b>Panel C.</b> Invasion of C38 and IB3-1 by <i>B. cenocepacia</i> LMG 16656 in presence of 0 and 10 mM GSH. Results represent means ± SD obtained by measuring <i>B. cenocepacia</i> LMG 16656 invasion ability in three independent experiments (*** p<0.0001). White bars: control cells; black bars: cells treated with 10 mM GSH. <b>Panel D.</b> Invasion of 9HTEo-, CFTE29o-, C38 and IB3-1 by <i>B. cenocepacia</i> 6L in presence of 0 and 10 mM GSH. Results are shown as % of intracellular bacteria recovered with respect to the bacteria added to the cell monolayer. The reported values are means ± SD obtained by measuring 6L invasion ability in three independent assays (** p<0.01). White bars: control cells; black bars: cells treated with 10 mM GSH.